| 摘要 |
<p>A pneumatic percussion tool having a reciprocable piston hammer with similar reduced diameter portions extending from opposite sides of an enlarged piston portion. Each reduced diameter portion includes an annular groove cooperable with associated inlet porting for admitting pressure air to act on the piston to deliver a percussion blow. The respective grooves are located at different positions with respect to the opposite impact end faces of the piston hammer and the hammer can be reversibly disposed in the tool cylinder to provide variable impact blow, blow frequency, and air consumption.</p> |
